On 10/3/2015 12:21 PM, Tony Hwang wrote:
Vic Smith wrote:
On Sat, 03 Oct 2015 10:50:46 -0700, Don Y
wrote:
Someone once claimed that AA and D cells were essentially the same
"internals", just different shells. I'd find that hard to believe
(unless it's akin to the "11 oz Coors" scam). One *hopes* the
big, heavy, bulky D cells are actually *giving* you something
for the extra size/weight!
They measure capacity in MaH. This is useful:
https://en.wikipedia.org/wiki/List_of_battery_sizes
With LED bulbs I'm satisfied with AA life-span.
It's amusing how 9v "transistor" batteries have fallen from
favor since the days of youth (in "transistor" radios). Aside
from the smoke/CO detectors, I can' think of anything that
uses them (so, why keep them on hand IN ANTICIPATION of a
failure?)
I don't know why they still equip smoke detectors with 9v.
But when I buy some more I'll look for AA equipped.
I see they sell them.
Our detectors battery is only back up during power failure.
That's the new trend and, AFAICT, required in new construction.
But, battery is still tested while running on AC power. For
our (dual AC/DC) units:
If any form of battery failure is detected the red LED light
will flash and the unit will “chirp” one time, followed by the
warning message “LOW BATTERY”. This cycle will occur once every
minute, and will continue for at least seven days.
Yeah, I *really* want to listen to that if it happens in the middle
of the night! (not!)
Note that the detector can be temporarily silenced for *nuisance*
alarms ("Dinner will be served at the sound of the smoke detector!")
but not for the low battery reminder (I guess they don't consider it
a NUISANCE to babble "LOW BATTERY" every minute for 10,080 consecutive
minutes!)
Also, the detector *claims* it will conspire with its peers to adjust
its sensitivity -- again, presumably, to minimize spurious alarms.
But, when the battery quits, it will nag you EVEN though you have
AC mains powering the unit! (OhMiGosh! What if the power fails
while the battery is low??)
Same with alarm clocks. Power failure is very rare in our
neighborhood. Longest was like 5 hours once years ago during ice
storm. This is there was one during severe thunderstorm, 20 mins.
We had a distribution transformer for the neighborhood catch fire
which cost us most of a day. Another time, a cable fire in a vault
(our utilities are below grade) ate up a day while new cables
were "pulled".
I have one watch runs on solar and equipped with 3 radios for time signal. Can
receive and sync time in NA, EU and Asia.
I have a couple of crank-powered radios -- along withone that has a
large *mainspring* that will drive the generator mechanism for a
full 15 minutes! And, UPS's serve for short term backup power;
plug a few CFLs into a UPS and the neighbors wonder why *you*
(appear!) to have power but they *don't*! : The batteries
in the electric wheelbarrow will keep the house "lit up"
for close to a day!
A friend is dropping off a genset for me to "rescue". This will allow
us to keep the freezer in the garage operational during outages as
well as the furnace (in the event it is a winter outage). Can't
do much for the ACbrrrr during an outage...